Concrete is a most useful and advantageous building material. Concrete is extremely durable, non-flammable, and demonstrates high compressive strengths. Concrete is also impervious to both wood destroying insects/vermin as well as dry rot. However, concrete also demonstrates limitations in adaptability and onsite modifications when compared to wood and other construction materials. For example, concrete may be easily molded and formed, from a plastic state, to a fully cured solid, in conformance with virtually any selected mold. However, modification of a fully cured cement material, by means of cutting, drilling or sanding is very limited as the material tends to fracture. In addition, assembly of concrete to other non-concrete materials also poses greater difficulties than other materials in that drilling, nailing and bolting concrete structures suffers from the same fracture failure inherent in this crystalline material.
The construction of onsite molds for forming structural elements is far more expensive then wood frame construction. Concrete block materials and construction techniques utilizing such materials reduces the cost of expensive onsite molds. Also, individual blocks are more easily handled and arranged in building desired structures. However, concrete blocks are inherently heavy and thus the cost of producing structures based on concrete block structural elements must include the increased cost of transporting such materials.
In order to lighten the weight of pre-formed concrete building materials, and, in certain instances, improve the fire-resistance thereof, lightweight concrete aggregate materials have been disclosed wherein cellulose fiber, one or more cements and potable water are utilized to form a lightweight aggregate concrete materials. U.S. Pat. No. 5,785,419 ('419) disclosed a lightweight building material comprised of a mixture of 66-89.5% Portland type I/Il cement; 0-23% fly ash; and 5.8 to 11.5% cellulose fiber. The aforementioned components are in dry form. The process disclosed in the '419 patent entails mixing the dry components with water in a ratio of 10 gallons of water to 68 pounds of dry component (cements, fly ash and fiber). More specifically, the mixing procedure of the '419 patent commences with the mixing of water and cellulose fiber first. Thereafter, cement and fly ash are added to the wet pulp and the four components are mixed for at least five minutes. Thereafter, excess water is compressed out of the mixture via a water extraction means so as to yield a dry cake-like material. The cake-like material is thereafter processed by a crumbler device so as to yield pellet like pieces of material which are allowed to cure.
The dry pellets of the '419 patent, formed of cement, fly ash and cellulose fiber, are thereafter mixed with sand/cement admixtures and water sufficient to hydrate the cement. The hydrated material is then placed in a hydraulic press/mold defining the desired construction material shape and allowed to cure. The resultant material is a lightweight concrete aggregate capable of being sanded, chiseled, drilled, sawed, nailed and bolted in a manner similar to as those techniques utilized in connection with wood construction materials.
As stated above, in practicing the aggregate cement process and methods of the prior art, such as, for example, those disclosed in the '419 patent, after mixing the saturated pulp fiber with the Portland cement and fly ash, excess water is compressed, squeezed or otherwise extracted from the mixture. Thereafter the cake-like resulting structure is mechanically crumbled into pellet like particles and allowed to cure. The cured particles are thereafter mixed with a fortifying admixture, additional cement and water in order to form a plastic aggregate mixture for use in structural and other molds. The aforementioned process and method require the extraction of excess water from an initial mix, an intermediate cure, addition of further amounts of water, cement and admixtures prior to providing a moldable material. The prior art, such as that disclosed by the '419 patent teaches the use of hydrated wet pulp or wet paper fiber for combination with other mixture materials. Hydrated pulp, already saturated with water, does not absorb fortifying solutions to the same extent as dried pulp. In addition, removing water from pulp, already treated with fly ash and or other fortifying agents, tends to cause the loss of such vital mixture components from the aggregate material it is intended to benefit. Furthermore, the addition of other admixture materials and cement, subsequent to initial cement, fly ash saturation of the pulp fiber during the initial mix, reduces the ability of such components to truly penetrate and fully incorporate the pulp fiber within the final aggregate matrix. Additionally, the steps of dehydration and rehydration of the material add additional steps, equipment, costs and time to the manufacturing process.
What is needed is a method and process for producing a lightweight aggregate cement, wherein excess water, and the fortifying agents therein, are not necessarily removed from the paper fiber to which they are intended to be incorporated and wherein all the water necessary to hydrate the cement component therein, is incorporated into an initial mix so as to obviate multiple curing stages. A process having less steps results in a simpler process having lower costs, less equipment and faster production.